Method of making explosive assemblies



Dec. 15, 1953 w. R. FARREN METHOD OF MAKING EXPLOSIVE ASSEMBLIES Filed June 25. 1948 WM U 911 N r R mm 0 FN T m R m .w

Y B .n F.

Patented Dec. 15, 1953 METHonoF-" AKING ASSEMBLIES William B. Farreng Kenn to.- Atlas Bowden Company;

ExPLos'Iv'rr Blitz squargsBaz assiglmr:

Wilmington Dot,

a corporationof Delaware; Application J ime=23, 1948i sen-amoe- 34-561 1 Glaim.

The present invention relates'litorexp'losivez as semblies.

An .object: of the invention is the provi'siont of an-.explosive assembly which is easy'to': use;

apparent from th'efolrounded by'aless sensitive or.1ower velocity or base charge, explosive. explosive has main, Often the base charge customary to initiate explosiveiassembliesrof the type just described by means. or; separate; primer be initiatedby blastingJcapsU Ordinary nitroglycerin dynamite; andipartibushell gathered explosive, or the core explosive may be inserted intoit later. i

The explosive assemblyofth'eepresent'invention oonveniently inarrufmatured V by first loosely in 1 place: of the-' mandrel and tying? the gathered portiontightly about-i the corereceptacle: The base charge: explosives m'ay' their be loaded" into the shell from tliecpposite" end" afterwhich that end may be closed in= any suitable-manner;

The-invention will be furtlier-dscribed iiT'cOnnection with the drawings in wliicli- V Figure 1 is a side elevation partly in section of an" assembly of tlieinventions" Figure 2 is-a fragmentary side elevation partlysection= in another modification of the invention;

sheil gatherediaboutfi-ai-lnamdreli and g I Figure 5' is; afragmentary side elevation ofa about a" core receptaclelieltl on" a Referring to Figurej 1 or the drawings, I *I is a shell offlexible material gatliered together-at' the top-by wire-tie I3soraetosurround and hold core endS-of-Which arwtwistedftogether and provided with loop 21% Keep is a: convenient" handle forthe assembly'an'dalso' fortwisting to tighten the assembly:

Figure 2' snows" :ise'riib'ij; somewhat similar- Parts shown in Figure to that shown in Figure 1. 2 which correspond to parts shown in Figure 1 Figures 3 and 4 show steps in the manufacture of the assembly of Figure 1. In Figure 3,

shell II is shown in the form of a cylindrical sube. Shell ll rests on base 23 which carries mandrel 25. Shell H is gathered about mandrel 25, as shown in Figure 4, and wire tie it is twisted around the gathered portion, shell H is then removed from mandrel 25, and core cartridge I5 is inserted in place of it. Wire tie it is then twisted by means of loop 2| to tighten shell ll about core 15. Base charge explosive I9 is then loaded into the open end of shell ii, and that end is wise closed.

Figure 5 shows a step in the manufacture of the assembly of Figure 2 corresponding'to the step shown in Figure 4 for the assembly of Figure 1. Core receptacle I5 is placed over mandrel 25, and shell H is gathered tightly about receptacle It by wire tie 2%. After the assembly is pulled from mandrel 25, capped and filled with explosive, the assembly shown in Figure 2 results. I

It is obvious that many different shell materialsmay be employed for the outer shell for the assembly of the invention.- The material used, however, should be sufficiently flexible to permit its being core receptacle. 0n the other hand it should be sufficiently rugged to withstand the rough handling often received by explosive assemblies of the present type. Heavy laminated paper in the form of spiral wound tubes is one of the most satisfactory materials available. It is easily worked when freshly made and the glue is still. wet. Cloth or flexible plastic materials also may be used.

While any convenient explosive material can be used for the base charge, compositions predominantly composed of ammonium nitrate are usually preferred from the point of view of cost and effectiveness of operation.

The core or primer explosive used in accord ance with the invention should be sufficiently sensitive to provide certainty of initiation. Soft core materials are usually preferable because they permit ready insertion of a blasting cap. However, hard TNT type materials may be used; though in such cases it is generally desirable to provide the core with a well for the reception of a blasting cap. Ordinary nitroglycerin dynamite, and particularly gelatin dynamite because of its water resisting properties, finds especial use as core materials. When dynamite is employed, it may be used in the usual paper cartridges in which it is commonly manufactured.

When the assembly or the invention is made up without a core explosive, the core receptacle should be suinciently rigid that it will withstand then crimped, capped, or otherproperly gathered about the the pressure of the base charge explosive. Ordinary mailing tube stock is highly effective for this purpose, although any other convenient material may be used.

When a cap is employed over the gathered end of the cartridge any conventional capping material or form of cap may be used. It is desirable that caps be made of frangible material so that the primer explosive may be conveniently pushed into place. Ethyl cellulose shrunk around the top is a good material, and so also is a lacquer film. r

If desired, the gathered portion of the assemblies of the invention may be sealed by applying adhesive to the joint between the assembly shell and the core receptacle, or water-proofing compound may be poured into the joint from either the inside or the outside of the shell;

Other tie materials than wire, as for example, cord or strap materials, may be employed in the assemblies of the invention.

The assemblies of the invention may include conventional cores in addition to the exposed ones specifically provided for by the invention.

Other modifications of the invention will be obvious to those skilled in the art.

What is claimed is:

A method for making an explosive assembly which comprises placing a cylindrical tube over a mandrel having a diameter substantially less than that of the tube, collapsing and gathering together the periphery of an end of'said tube about said mandrel, tying the collapsed and gathered portion of said tube, withdrawing said mandrel from said gathered portion, inserting a core cartridge of gelatin dynamite in place of said mandrel, tying said collapsed and gathered portion about said core, filling said shell from the opposite end with an ammonium nitrate explosive, and closing said opposite end.

WILLIAM R. FARREN.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,824,141 Hill :Sept. 22, 1931 1,890,726 Farren Dec. 13, 1932 2,069,612 Kirst et a1 Feb. 2, 1937 2,448,658 Carey Sept. '7, 1948 FOREIGN PATENTS Number Country Date 2,143 Great Britain of 1884 2,753 Great Britain June 2, 1883 14,548 Great Britain July 14, 1894 449,909 Great Britain July 6, 1936 108,708 Germany Feb. 19, 1900 

